Solid-state image sensor for phase difference detection, method of manufacturing the same, and electronic device

ABSTRACT

A more preferable pixel for detecting a focal point may be formed by using a photoelectric converting film. A solid-state image sensor includes a first pixel including a photoelectric converting unit formed of a photoelectric converting film and first and second electrodes which interpose the same from above and below in which at least one of the first and second electrodes is a separated electrode separated for each pixel, and a second pixel including the photoelectric converting unit in which the separated electrode is formed to have a planar size smaller than that of the first pixel and a third electrode extending at least to a boundary of the pixel is formed in a region which is vacant due to a smaller planar size. The present disclosure is applicable to the solid-state image sensor and the like, for example.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/521,718, filed Apr. 25, 2017, which is a national stage applicationunder 35 U.S.C. 371 and claims the benefit of PCT Application No.PCT/JP2015/079820 having an international filing date of Oct. 22, 2015,which designated the United States, which PCT application claimed thebenefit of Japanese Patent Application No. 2014-225190 filed Nov. 5,2014, the disclosures of which are incorporated herein by reference intheir entirety.

TECHNICAL FIELD

The present disclosure relates to a solid-state image sensor, a methodof manufacturing the same, and an electronic device, and especiallyrelates to the solid-state image sensor capable of forming a morepreferable pixel for detecting a focal point by using a photoelectricconverting film, the method of manufacturing the same, and theelectronic device.

BACKGROUND ART

A solid-state image sensor in which a semiconductor is used is mountedon many devices such as a digital camera, a video camera, a monitoringcamera, a copying machine, and a fax machine. Recently, a so-called CMOSimage sensor manufactured by a complementary metal oxide semiconductor(CMOS) process together with a peripheral circuit is often used as thesolid-state image sensor.

There is the CMOS image sensor in which a method of using pixels fordetecting a focal point with sensitivities asymmetrical with respect toa light incident angle is adopted as an automatic focusing function of acamera. For example, in Patent Document 1, a photodiode in a pixel isdivided into two and one of them with a smaller area is used fordetecting a focal point as a method of realizing the pixel for detectinga focal point.

Also, recently, an image sensor in which an organic semiconductor and aninorganic compound semiconductor are used as a photoelectric convertingfilm is developed. This generally has an element structure including thephotoelectric converting film and electrodes interposing the same fromabove and below in which at least one of the upper and lower electrodesis separated for each pixel. Herein also, a method of using the pixelfor detecting a focal point is suggested.

In Patent Document 2, an organic photoelectric converting element alsohaving a color filter function arranged with the same optical pathlength as a silicon photodiode of a certain pixel is divided into two inthe pixel and used as a pair, and according to this, light withdifferent phase difference is detected and a focal point may bedetected. Patent Document 3 enables focal point detection by using apair of pixels provided with a light shielding film on a light incidentside in an organic photoelectric converting element for detecting phasedifference.

CITATION LIST Patent Document

-   Patent Document 1: Japanese Patent Application Laid-Open No.    2012-37777-   Patent Document 2: Japanese Patent Application Laid-Open No.    2013-145292-   Patent Document 3: Japanese Patent Application Laid-Open No.    2014-67948

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However, since a photoelectric converting film for detecting a focalpoint also serves as color filters in Bayer arrangement in the method ofrealizing in Patent Document 2, it is required to separate thephotoelectric converting film for each pixel. Therefore, dark currentdue to separation of the photoelectric converting film might bedeteriorated.

In the realizing method in Patent Document 3 in which the lightshielding film is used, when a photodiode is provided on a silicon layerbelow a photoelectric converting film, light received there is alsoshielded and an obtained signal becomes smaller.

The present disclosure is achieved in view of such a condition, and anobject thereof is to form a more preferable pixel for detecting a focalpoint by using the photoelectric converting film.

Solutions to Problems

A solid-state image sensor according a first aspect of the presentdisclosure is provided with a first pixel including a photoelectricconverting unit formed of a photoelectric converting film and first andsecond electrodes which interpose the photoelectric converting film fromabove and below in which at least one of the first and second electrodesis a separated electrode separated for each pixel, and a second pixelincluding the photoelectric converting unit in which the separatedelectrode is formed to have a planar size smaller than the planar sizeof the separated electrode of the first pixel and a third electrodeextending at least to a boundary of the pixel is formed in a regionwhich is vacant due to a smaller planar size.

A method of manufacturing a solid-state image sensor according to asecond aspect of the present disclosure forms a first pixel including aphotoelectric converting unit formed of a photoelectric converting filmand first and second electrodes which interpose the photoelectricconverting film from above and below in which at least one of the firstand second electrodes is a separated electrode separated for each pixel,and a second pixel including the photoelectric converting unit in whichthe separated electrode is formed to have a planar size smaller than theplanar size of the separated electrode of the first pixel and a thirdelectrode extending at least to a boundary of the pixel is formed in aregion which is vacant due to a smaller planar size.

An electronic device according to a third aspect of the presentdisclosure is provided with a solid-state image sensor including a firstpixel including a photoelectric converting unit formed of aphotoelectric converting film and first and second electrodes whichinterpose the photoelectric converting film from above and below inwhich at least one of the first and second electrodes is a separatedelectrode separated for each pixel, and a second pixel including thephotoelectric converting unit in which the separated electrode is formedto have a planar size smaller than the planar size of the separatedelectrode of the first pixel and a third electrode extending at least toa boundary of the pixel is formed in a region which is vacant due to asmaller planar size.

In the first to third aspects of the present disclosure, a first pixelincluding a photoelectric converting unit formed of a photoelectricconverting film and first and second electrodes which interpose thephotoelectric converting film from above and below in which at least oneof the first and second electrodes is a separated electrode separatedfor each pixel, and a second pixel including the photoelectricconverting unit in which the separated electrode formed to have a planarsize smaller than the planar size of the separated electrode of thefirst pixel and a third electrode extending at least to a boundary ofthe pixel is formed in a region which is vacant due to a smaller planarsize are provided.

The solid-state image sensor and the electronic device may beindependent devices or may be modules incorporated in other devices.

Effects of the Invention

According to the first to third aspects of the present disclosure, amore preferable pixel for detecting a focal point may be formed by usinga photoelectric converting film.

Meanwhile, the effect is not especially limited to the effects describedherein; this may also any effect described in the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view illustrating a schematic configuration of a solid-stateimage sensor according to the present disclosure.

FIG. 2 is a cross-sectional configuration diagram illustrating across-sectional configuration of a normal pixel.

FIG. 3 is a view illustrating a planar layout of a lower electrode of afirst embodiment.

FIG. 4 is a cross-sectional configuration diagram taken along lineY1-Y1′ in FIG. 3.

FIG. 5 is a cross-sectional configuration diagram taken along lineY2-Y2′ in FIG. 3.

FIG. 6 is a view illustrating a planar layout of a lower electrode of asecond embodiment.

FIG. 7 is a cross-sectional configuration diagram taken along lineY11-Y11′ in FIG. 6.

FIG. 8 is a view illustrating a planar layout of a third embodiment.

FIG. 9 is a cross-sectional configuration diagram taken along lineX11-X11′ in FIG. 8.

FIG. 10 is a cross-sectional configuration diagram taken along lineY21-X21′ in FIG. 8.

FIG. 11 is a cross-sectional configuration diagram taken along lineY22-Y22′ in FIG. 8.

FIG. 12 is a view illustrating a variation of the third embodiment.

FIG. 13 is a view illustrating a variation of the third embodiment.

FIG. 14 is a cross-sectional configuration diagram of a pixel of afourth embodiment.

FIG. 15 is a view illustrating a layout example of color filters.

FIG. 16 is a cross-sectional configuration diagram of a pixel of a fifthembodiment.

FIG. 17 is a cross-sectional configuration diagram of a pixel of a sixthembodiment.

FIGS. 18A to 18D are a view illustrating a method of manufacturing ofthe first embodiment.

FIGS. 19A to 19D are a view illustrating the method of manufacturing ofthe first embodiment.

FIGS. 20A to 20D are a view illustrating the method of manufacturing ofthe first embodiment.

FIGS. 21A to 21D are a view illustrating the method of manufacturing ofthe first embodiment.

FIGS. 22A and 22B are a view illustrating the method of manufacturing ofthe first embodiment.

FIGS. 23A and 23B are a view illustrating the method of manufacturing ofthe first embodiment.

FIGS. 24A and 24B are a view illustrating the method of manufacturing ofthe first embodiment.

FIGS. 25A and 25B are a view illustrating the method of manufacturing ofthe first embodiment.

FIG. 26 is a block diagram illustrating a configuration example of animaging device as an electronic device according to the presentdisclosure.

MODE FOR CARRYING OUT THE INVENTION

A mode for carrying out the present disclosure (hereinafter, referred toas an embodiment) is hereinafter described. Meanwhile, the descriptionis given in the following order.

1. Schematic Configuration Example of Solid-State Image Sensor

2. First Embodiment of Pixel (Configuration in Which Each of Pair ofPhase Difference Pixels Includes Dummy Pixel)

3. Second Embodiment of Pixel (Configuration in Which Pair of PhaseDifference Pixels Includes Shared Dummy Pixel)

4. Third Embodiment of Pixel (Configuration in Which Element SeparatingElectrode Is Extended to Phase Difference Pixel)

5. Fourth Embodiment of Pixel (First Configuration in WhichPhotoelectric Converting Film Receives Light of All Wavelengths)

6. Fifth Embodiment of Pixel (Second Configuration in WhichPhotoelectric Converting Film Receives Light of All Wavelengths)

7. Sixth Embodiment of Pixel (Third Configuration in Which PhotoelectricConverting Film Receives Light of All Wavelengths)

8. Manufacturing Method of First Embodiment

9. Application Example to Electronic Device

<1. Schematic Configuration Example of Solid-State Image Sensor>

FIG. 1 illustrates a schematic configuration of a solid-state imagesensor according to the present disclosure.

A solid-state image sensor 1 in FIG. 1 includes a pixel array unit 3obtained by arranging pixels 2 in a two-dimensional manner to form amatrix on a semiconductor substrate 12 formed of silicon (Si), forexample, as a semiconductor, and a peripheral circuit unit around thesame. The peripheral circuit unit includes a vertical driving circuit 4,a column signal processing circuit 5, a horizontal driving circuit 6, anoutput circuit 7, a control circuit 8 and the like.

The pixels 2 arranged in a two-dimensional manner to form a matrix inthe pixel array unit 3 include a normal pixel 2X which generates asignal for generating an image and a phase difference pixel 2P whichgenerates a signal for detecting a focal point as described later withreference to FIG. 3 and the like. There also is a case in which a dummypixel 2D is arranged adjacent to the phase difference pixel 2P.

The vertical driving circuit 4 formed of a shift register, for example,selects pixel driving wiring 10, supplies a pulse for driving the pixel2 to the selected pixel driving wiring 10, and drives the pixels 2 in arow unit. That is to say, the vertical driving circuit 4 sequentiallyselects to scan the pixels 2 in the pixel array unit 3 in a row unit ina vertical direction and supplies a pixel signal based on a signalcharge generated according to a light receiving amount by aphotoelectric converting unit of each pixel 2 to the column signalprocessing circuit 5 through a vertical signal line 9.

The column signal processing circuit 5 arranged for each column of thepixels 2 performs signal processing such as noise removal on the signalsoutput from the pixels 2 of one row for each pixel column. For example,the column signal processing circuit 5 performs the signal processingsuch as correlated double sampling (CDS) for removing a fixed patternnoise specific to the pixel and AD conversion.

The horizontal driving circuit 6 formed of a shift register, forexample, sequentially selects the column signal processing circuits 5 bysequentially outputting horizontal scanning pulses and outputs the pixelsignal from each of the column signal processing circuits 5 to ahorizontal signal line 11.

The output circuit 7 performs predetermined signal processing on thesignals sequentially supplied from the column signal processing circuits5 through the horizontal signal line 11 to output through an outputterminal 13. There is a case in which the output circuit 7 merelybuffers, for example, or a case in which this performs black leveladjustment, column variation correction, and various types of digitalsignal processing.

The control circuit 8 receives an input clock and data which designatesan operation mode and the like, and also outputs data such as internalinformation of the solid-state image sensor 1. That is, the controlcircuit 8 generates a clock signal and a control signal which serve as areference for operation of the vertical driving circuit 4, the columnsignal processing circuit 5, the horizontal driving circuit 6 and thelike on the basis of a vertical synchronization signal, a horizontalsynchronization signal, and a master clock. The control circuit 8 thenoutputs the generated clock signal and control signal to the verticaldriving circuit 4, the column signal processing circuit 5, thehorizontal driving circuit 6, and the like.

The solid-state image sensor 1 configured in the above-described manneris a so-called column AD type CMOS image sensor in which the columnsignal processing circuit 5 which performs the CDS processing and ADconversion processing is arranged for each pixel column.

<2. First Embodiment of Pixel>

<Cross-Sectional Configuration of Normal Pixel>

A cross-sectional configuration of a normal pixel of a solid-state imagesensor 1 is described with reference to FIG. 2.

FIG. 2 is a view illustrating the cross-sectional configuration of anormal pixel 2X of the solid-state image sensor 1 in FIG. 1.

Photodiodes PD1 and PD2 by PN junction are formed in a depth directionby forming second conductivity type (for example, N-type) semiconductorregions 42 and 43 so as to be stacked in the depth direction in a firstconductivity type (for example, P-type) semiconductor region 41 of asemiconductor substrate 12. The photodiode PD1 including thesemiconductor region 42 as a charge accumulation region is an inorganicphotoelectric converting unit which receives blue light to performphotoelectric conversion, and the photodiode PD2 including thesemiconductor region 43 as a charge accumulation region is an inorganicphotoelectric converting unit which receives red light to perform thephotoelectric conversion.

A plurality of pixel transistors which reads the charges accumulated inthe photodiodes PD1 and PD2 and a multi-layer wiring layer 44 formed ofa plurality of wiring layers and an interlayer insulating film areformed on a surface side (lower side in the drawing) of thesemiconductor substrate 12. Meanwhile, the multi-layer wiring layer 44is not illustrated in detail in FIG. 2. A plurality of pixel transistorsis formed of four MOS transistors which are a transfer transistor, aselection transistor, a reset transistor, and an amplificationtransistor, for example.

A conductive plug 46 for extracting the charge obtained by thephotoelectric conversion by a photoelectric converting film 52 to bedescribed later to a side of the multi-layer wiring layer 44 is formedon the semiconductor substrate 12 so as to penetrate (the semiconductorregion 41 of) the semiconductor substrate 12. An SiO2 or SiN insulatingfilm 47 is formed on an outer periphery of the conductive plug 46 so asto inhibit short-circuit with the semiconductor region 41.

The conductive plug 46 is connected to a floating diffusion unit (FDunit) 49 formed of a second conductivity type (for example, N-type)semiconductor region in the semiconductor substrate 12 by means of metalwiring 48 formed in the multi-layer wiring layer 44. The FD unit 49 is aregion in which the charge obtained by the photoelectric conversion bythe photoelectric converting film 52 is temporarily held before beingread. The charge held in the FD unit 49 is output to the column signalprocessing circuit 5 on a subsequent stage through the amplificationtransistor and the like as is the case with the charges generated by thephotodiodes PD1 and PD2. However, the transfer transistor required inthe photodiodes PD1 and PD2 is not required when the charge generated bythe photoelectric converting film 52 is output as a signal. Therefore,the photoelectric conversion using the photoelectric converting film 52has an advantage that light receiving areas of the photodiodes PD1 andPD2 are not narrowed.

A transparent insulating film 51 formed of two or three layers of ahafnium oxide (HfO₂) film and a silicon oxide film is formed, forexample, on an interface on a rear surface side (upper side in thedrawing) of the semiconductor substrate 12.

The photoelectric converting film 52 is arranged above the transparentinsulating film 51 so as to be interposed between a lower electrode 53 abelow the same and an upper electrode 53 b above the same. Out of aregion in which the photoelectric converting film 52 is formed, a regioninterposed between the lower electrode 53 a and the upper electrode 53 bis the region in which incident light is subjected to the photoelectricconversion; the photoelectric converting film 52, the lower electrode 53a, and the upper electrode 53 b form a photoelectric converting unit 61.As a film which performs the photoelectric conversion on greenwavelength light, the photoelectric converting film 52 is formed of anorganic photoelectric converting material containing a rhodamine dye, amerocyanine dye, or quinacridone, for example. The lower electrode 53 aand the upper electrode 53 b are formed of an indium tin oxide (ITO)film, an indium zinc oxide film and the like, for example.

Meanwhile, in a case in which the photoelectric converting film 52 is afilm which performs the photoelectric conversion on red wavelengthlight, an organic photoelectric converting material containing aphthalocyanine dye may be used, for example. Also, in a case of the filmwhich performs the photoelectric conversion on blue wavelength light, anorganic photoelectric converting material containing a coumarin dye,tris(8-hydroxyquinoline) aluminum (Alq3), the merocyanine dye and thelike may be used.

Although the upper electrode 53 b is formed on an entire surface so asto be shared by all the pixels, the lower electrode 53 a is formed foreach pixel and is connected to the conductive plug 46 of thesemiconductor substrate 12 by means of metal wiring 54 penetrating thetransparent insulating film 51. The metal wiring 54 formed of materialssuch as tungsten (W), aluminum (Al), and copper (Cu) is also formed in aplanar direction at predetermined depth of the transparent insulatingfilm 51 and also serves as an interpixel light shielding film 55 whichinhibits the light from entering an adjacent pixel.

A high refractive index layer 56 is formed of an inorganic film such asa silicon nitride film (SiN), silicon oxynitride film (SiON), andsilicon carbide (SiC) on an upper surface of the upper electrode 53 b.Also, an on-chip lens 57 is formed above the high refractive index layer56. The silicon nitride film (SiN) or a resin material such as a styreneresin, an acrylic resin, a styrene acrylic copolymer resin, or asiloxane resin, for example, is used as a material of the on-chip lens57. In this pixel structure, since a distance between the photoelectricconverting film 52 and the on-chip lens 57 is short, light incidentangle dependency is smaller in a phase difference pixel 2P, so that thehigh refractive index layer 56 has an effect of enlarging a refractionangle and improving light condensing efficiency.

In FIG. 2, three normal pixels 2X configured in the above-describedmanner are arranged side by side.

The solid-state image sensor 1 in which the normal pixels 2X formed inthis manner are arranged in a two-dimensional manner is a rear surfaceirradiation type

CMOS solid-state image sensor in which the light enters from a rearsurface side on an opposite side of the surface side of thesemiconductor substrate 12 on which the multi-layer wiring layer 44 isformed.

Also, the solid-state image sensor 1 is a longitudinal directionspectral solid-state image sensor which performs the photoelectricconversion by the photoelectric converting film 52 formed above thesemiconductor substrate (silicon layer) 12 on the green light andperforms the photoelectric conversion by the photodiodes PD1 and PD2 inthe semiconductor substrate 12 on the blue light and red light.

<Planar Layout of Lower Electrode>

FIG. 3 is a view illustrating a planar layout of the lower electrode inthe pixel array unit 3.

As illustrated in FIG. 3, out of the pixels 2 arranged in atwo-dimensional manner in the pixel array unit 3, in the normal pixel2X, the lower electrode 53 a is formed for each pixel. Thecross-sectional view illustrated in FIG. 2 corresponds a cross-sectionalview of a portion in which the three normal pixels 2X are arranged in ahorizontal direction indicated by line X1-X1′ in FIG. 3, for example.

On the other hand, the pixels 2 arranged in a two-dimensional manner inthe pixel array unit 3 include the pixel 2 including a lower electrode53 c a planar size of which is made smaller than that of the lowerelectrode 53 a of the normal pixel 2X and the pixel 2 including a lowerelectrode 53 d enlarged to a region which is vacant due to a decrease insize of the lower electrode 53 c.

The pixel 2 including the downsized lower electrode 53 c is the phasedifference pixel 2P which generates a signal for detecting a focal pointand the pixel 2 including the enlarged lower electrode 53 d is a dummypixel 2D arranged adjacent to the phase difference pixel 2P.

A pair (two) of the phase difference pixels 2P configured such thatsensitivities are asymmetrical with respect to a light incident angle isarranged in the pixel array unit 3. The two phase difference pixels 2Pwhich form a pair are represented as a type A phase difference pixel2P_(A) and a type B phase difference pixel 2P_(B). Also, the dummy pixel2D arranged adjacent to the phase difference pixel 2P_(A) is representedas a dummy pixel 2D_(A) and the dummy pixel 2D arranged adjacent to thephase difference pixel 2P_(B) is represented as a dummy pixel 2D_(B).

In an example in FIG. 3, the phase difference pixel 2P_(A) is the pixelin which the lower electrode 53 c is formed so as to receive light onlyby a left side in the pixel as compared to the normal pixel 2X, and thephase difference pixel 2P_(B) is the pixel in which the lower electrode53 c is formed only on a right side in the pixel such that aphotoelectric conversion region is symmetrical to that in the phasedifference pixel 2P_(A).

Meanwhile, although a pair of the phase difference pixel 2P_(A) and thedummy pixel 2D_(A) and a pair of the phase difference pixel 2P_(B) andthe dummy pixel 2D_(B) are arranged so as to be adjacent in alongitudinal direction (vertical direction) in the example in FIG. 3,they are not necessarily arranged so as to be adjacent in thelongitudinal direction. For example, the pair of the phase differencepixel 2P_(A) and the dummy pixel 2D_(A) and the pair of the phasedifference pixel 2P_(B) and the dummy pixel 2D_(B) may be arranged withone or more pixels interposed therebetween or arranged so as to beadjacent in a lateral direction (horizontal direction).

Also, although the lower electrodes 53 c of the phase difference pixels2P_(A) and 2P_(B) are downsized in the lateral direction (horizontaldirection) as compared to the lower electrode 53 a in the normal pixel2X in the example in FIG. 3, they may also be downsized in thelongitudinal direction (vertical direction). When the lower electrodes53 c of the phase difference pixels 2P_(A) and 2P_(B) are downsized inthe longitudinal direction, the phase difference pixel 2P_(A) and thedummy pixel 2D_(A) are arranged so as to be adjacent in the longitudinaldirection and the phase difference pixel 2P_(B) and the dummy pixel2D_(B) are also arranged so as to be adjacent in the longitudinaldirection.

Furthermore, the pair of the phase difference pixels 2P_(A) and 2P_(B)including the lower electrodes 53 c downsized in the lateral directionand the pair of the phase difference pixels 2P_(A) and 2P_(B) includingthe lower electrodes 53 c downsized in the longitudinal direction may bemixed in the pixel array unit 3.

Displacement in image occurs between the pixel signal from the phasedifference pixel 2P_(A) and the pixel signal from the phase differencepixel 2P_(B) because the lower electrodes 53 c are formed in differentpositions. It is possible to realize automatic focusing by calculating adefocusing amount by calculating a phase displacement amount from thedisplacement in image to adjust (move) an imaging lens.

<Cross-Sectional Configuration of Phase Difference Pixel>

FIG. 4 illustrates a cross-sectional configuration taken along lineY1-Y1′ in FIG. 3 in which one normal pixel 2X and the pair of the phasedifference pixel 2P_(A) and the dummy pixel 2D_(A) are included.

FIG. 5 illustrates a cross-sectional configuration taken along lineY2-Y2′ in FIG. 3 in which one normal pixel 2X and the pair of the phasedifference pixel 2P_(B) and the dummy pixel 2D_(B) are included.

As illustrated in FIGS. 4 and 5, the lower electrode 53 c of the phasedifference pixel 2P (2P_(A) or 2P_(B)) is downsized in the lateraldirection (horizontal direction) as compared to the lower electrode 53 aof the normal pixel 2X and the lower electrode 53 d of the dummy pixel2D (2D_(A) or 2D_(B)) is extended to a region which is vacant due todownsizing to be formed. Although an interval in the planar directionbetween the lower electrode 53 c of the phase difference pixel 2P andthe lower electrode 53 d of the dummy pixel 2D is set to be the same asthe interval between the lower electrodes 53 a of two adjacent normalpixels 2X, they are not necessarily the same.

In the phase difference pixel 2P and the dummy pixel 2D, theconfiguration other than the lower electrodes 53 c and 53 d is similarto that of the normal pixel 2X. Therefore, B signals and R signalsgenerated by the photodiodes PD1 and PD2 of the phase difference pixel2P and the dummy pixel 2D may be utilized as the signals for generatingan image.

A G signal generated by the photoelectric converting unit 61, that is tosay, the photoelectric converting film 52, the upper electrode 53 b, andthe lower electrode 53 c of the phase difference pixel 2P is output tothe FD unit 49 through the metal wiring 54 and the conductive plug 46 tobe utilized as the signal for detecting a focal point. The G signal forgenerating an image of the phase difference pixel 2P is calculated byinterpolation from the G signals of a plurality of normal pixels 2Xaround the phase difference pixel 2P, for example.

On the other hand, the G signal generated by the photoelectricconverting unit 61, that is to say, the photoelectric converting film52, the upper electrode 53 b, and the lower electrode 53 d of the dummypixel 2D is output to the FD unit 49 through the metal wiring 54 and theconductive plug 46, but this is discharged without being utilized. The Gsignal for generating an image of the dummy pixel 2D is also calculatedby the interpolation from the G signals of a plurality of normal pixels2X around the dummy pixel 2D, for example.

According to the first embodiment of the phase difference pixel 2Pconfigured in the above-described manner, it is not required to form alight shielding film on an upper surface of the photoelectric convertingfilm 52 for each color, so that it is possible to realize the phasedifference pixel while avoiding an increase in the number of steps forforming the light shielding film. Also, it is not required to separatethe photoelectric converting film 52 between the pixels, so that it ispossible to inhibit dark current generated when the photoelectricconverting film 52 is separated between the pixels.

Therefore, it is possible to form a more preferable phase differencepixel 2P for detecting a focal point by using the photoelectricconverting film 52 formed on an outer side of the semiconductorsubstrate 12.

Meanwhile, in the pixel structure illustrated as the first embodiment,since the photoelectric converting film 52 performs the photoelectricconversion on the green light, the G signal output from the phasedifference pixel 2P is used as the signal for detecting a focal point;however, it is possible to arbitrarily select the color of the light onwhich the photoelectric conversion is performed by the photoelectricconverting film 52. That is to say, in the longitudinal directionspectral solid-state image sensor, it is possible to appropriatelydetermine the color of the light on which the photoelectric conversionis performed by the photoelectric converting film 52 formed above thesemiconductor substrate 12 and the colors of the light on which thephotoelectric conversion is performed by the photodiodes PD1 and PD2 inthe semiconductor substrate 12.

<3. Second Embodiment of Pixel>

<Planar Layout of Lower Electrode>

Next, a second embodiment is described. Meanwhile, in the description ofthe second embodiment and thereafter, the description of a portioncorresponding to that in other embodiments indicated with the samereference sign as that of the above-described other embodiments isappropriately omitted and only a different portion is described. Anormal pixel of the second embodiment is similar to that of theabove-described first embodiment, so that only a phase difference pixelis described.

FIG. 6 is a view illustrating a planar layout of a lower electrode in apixel array unit 3.

In the second embodiment, phase difference pixels 2P_(A) and 2P_(B) arearranged in a linear manner with a dummy pixel 2D interposedtherebetween. That is to say, the phase difference pixel 2P_(A), thedummy pixel 2D, and the phase difference pixel 2P_(B) are arranged inthe pixel array unit 3 in this order. Therefore, the dummy pixel 2D isarranged adjacent to the phase difference pixels 2P_(A) and 2P_(B); thisserves as a dummy pixel 2D_(A) arranged adjacent to the phase differencepixel 2P_(A) and a dummy pixel 2D_(B) arranged adjacent to the phasedifference pixel 2P_(B). Such dummy pixel 2D is represented as a dummypixel 2D_(AB).

In the second embodiment, the phase difference pixel 2P_(A) includes alower electrode 53 c formed so as to receive light only on a left sidein the pixel as in the first embodiment. The phase difference pixel2P_(B) includes the lower electrode 53 c only on a right side in thepixel such that a photoelectric conversion region is symmetrical to thatof the phase difference pixel 2P_(A).

Then, a lower electrode 53 d of the dummy pixel 2D_(AB) arranged in thecenter is extended to regions of the phase difference pixels 2P_(A) and2P_(B) which are vacant due to downsizing of the lower electrodes 53 cto be formed. In other words, the lower electrode 53 d of the dummypixel 2D_(AB) is formed so as to extend to sides of the phase differencepixels 2P_(A) and 2P_(B) to lie across three pixels.

Meanwhile, although the phase difference pixel 2P_(A), the dummy pixel2D, and the phase difference pixel 2P_(B) are arranged in a linearmanner in a horizontal direction in this order in the example in FIG. 6,it is also possible to configure such that they are arranged in a linearmanner in a vertical direction.

<Cross-Sectional Configuration of Phase Difference Pixel>

FIG. 7 illustrates a cross-sectional configuration taken along lineY11-Y11′ in FIG. 6 including the phase difference pixel 2P_(A), thedummy pixel 2D_(AB), and the phase difference pixel 2P_(B).

As illustrated in FIG. 7, the lower electrodes 53 c of the phasedifference pixels 2P_(A) and 2P_(B) are downsized in a lateral direction(horizontal direction) as compared to a lower electrode 53 a of a normalpixel 2X and the lower electrode 53 d of the dummy pixel 2D_(AB) isextended to the regions which are vacant due to the downsizing to beformed.

In the phase difference pixels 2P_(A) and 2P_(B), a charge generated ina region interposed between an upper electrode 53 b and the lowerelectrode 53 c out of a region of a photoelectric converting film 52 isaccumulated in a FD unit 49. Positions in which the lower electrodes 53c are formed in the phase difference pixels 2P_(A) and 2P_(B) aresymmetrical to each other. Displacement in image occurs between pixelsignals from the phase difference pixels 2P_(A) and 2P_(B) because thelower electrodes 53 c are formed in different positions. It is possibleto realize automatic focusing by calculating a defocusing amount bycalculating a phase displacement amount from the displacement in imageto adjust (move) an imaging lens.

According to the second embodiment of the phase difference pixel 2Pconfigured in the above-described manner, it is not required to form alight shielding film on an upper surface of the photoelectric convertingfilm 52 for each color, so that it is possible to realize the phasedifference pixel while avoiding an increase in the number of steps forforming the light shielding film. Also, it is not required to separatethe photoelectric converting film 52 between the pixels, so that it ispossible to inhibit dark current generated when the photoelectricconverting film 52 is separated between the pixels.

Therefore, it is possible to form a more preferable phase differencepixel 2P for detecting a focal point by using the photoelectricconverting film 52 formed on an outer side of the semiconductorsubstrate 12.

<4. Third Embodiment of Pixel>

<Planar Layout of Lower Electrode>

Next, a third embodiment is described.

FIG. 8 is a view illustrating a planar layout of a lower electrode in apixel array unit 3.

Meanwhile, in FIG. 8, a broken line indicating a boundary of each pixel2 illustrated in FIGS. 3 and 6 is omitted in order to make the drawingmore visible.

In the third embodiment, an element separating electrode 81 whichseparates pixels (elements) is formed between lower electrodes 53 a and53 c adjacent to each other. A material similar to that of the lowerelectrodes 53 a and 53 c such as an indium tin oxide (ITO) film and anindium zinc oxide film, for example, may be used as a material of theelement separating electrode 81. The element separating electrode 81 isformed between the lower electrodes 53 a and 53 c adjacent to each otherin a vertical direction and in a horizontal direction, so that this isformed into a lattice shape as illustrated in FIG. 8.

Predetermined fixed potential is applied to the element separatingelectrode 81. According to this, it is possible to prevent capacitycoupling between the adjacent pixels and inhibit an after image bycollecting a charge generated between the pixels.

A phase difference pixel 2P_(A) includes the lower electrode 53 c formedso as to receive light only on a left side in the pixel as in the firstembodiment. The phase difference pixel 2P_(B) includes the lowerelectrode 53 c only on a right side in the pixel such that aphotoelectric conversion region is symmetrical to that of the phasedifference pixel 2P_(A).

Then, the element separating electrode 81 is formed in a region which isvacant due to downsizing of the lower electrode 53 c of the phasedifference pixel 2P_(A) so as to be extended from a pixel boundary line.The element separating electrode 81 is formed also in a region which isvacant due to the downsizing of the lower electrode 53 c of the phasedifference pixel 2P_(B) so as to be extended from the pixel boundaryline. That is to say, each of the phase difference pixels 2P_(A) and2P_(B) has a configuration in which the element separating electrode 81adjacent thereto is extended to the region which is vacant due to thedownsized lower electrode 53 c to be formed.

Positions in which the lower electrodes 53 c are formed in the phasedifference pixels 2P_(A) and 2P_(B) configured in the above-describedmanner are symmetrical to each other. Displacement in image occursbetween pixel signals from the phase difference pixels 2P_(A) and 2P_(B)because the lower electrodes 53 c are formed in different positions. Itis possible to realize automatic focusing by calculating a defocusingamount by calculating a phase displacement amount from the displacementin image to adjust (move) an imaging lens.

Meanwhile, although the lower electrodes 53 c of the phase differencepixels 2P_(A) and 2P_(B) are downsized in a lateral direction(horizontal direction) as compared to the lower electrode 53 a of anormal pixel 2X in the example in FIG. 8, they may also be downsized ina longitudinal direction (vertical direction). In this case, the elementseparating electrode 81 which separates the upper and lower electrodes53 a and 53 c is formed so as to be extended in the longitudinaldirection in each of the phase difference pixels 2P_(A) and 2P_(B).

<Cross-Sectional Configuration of Pixel>

FIG. 9 is a cross-sectional configuration diagram taken along lineX11-X11′ in FIG. 8 including two normal pixels 2X.

FIG. 10 is a cross-sectional configuration diagram taken along lineY21-Y21′ in FIG. 8 including one normal pixel 2X and one phasedifference pixel 2P_(A).

FIG. 11 is a cross-sectional configuration diagram taken along lineY22-Y22′ in FIG. 8 including one normal pixel 2X and one phasedifference pixel 2P_(B).

As illustrated in FIG. 9, in a portion in which the normal pixels 2X areadjacent to each other, the element separating electrode 81 is formed ina position on the pixel boundary in a planar direction and in the sameposition as that of the lower electrode 53 a in a depth direction. Theelement separating electrode 81 is connected to metal wiring 82 formedbelow the same and predetermined fixed potential is applied to theelement separating electrode 81 through the metal wiring 82.

As illustrated in FIG. 10, in a portion in which the phase differencepixel 2P_(A) and the normal pixel 2X are adjacent to each other, theelement separating electrode 81 is formed in the region which is vacantdue to the downsizing of the lower electrode 53 c of the phasedifference pixel 2P_(A) so as to be extended from the pixel boundaryline.

Also, as illustrated in FIG. 11, in a portion in which the phasedifference pixel 2P_(B) and the normal pixel 2X are adjacent to eachother, the element separating electrode 81 is formed in the region whichis vacant due to the downsizing of the lower electrode 53 c of the phasedifference pixel 2P_(B) so as to be extended from the pixel boundaryline.

The extended element separating electrode 81 is connected to the metalwiring 82 formed below the same and predetermined fixed potential isapplied to the element separating electrode 81 also in FIGS. 10 and 11as in FIG. 9. The charge generated by a photoelectric converting film 52interposed between the extended element separating electrode 81 and anupper electrode 53 b is not connected to the FD unit 49 and is notextracted as a signal.

According to the third embodiment of the phase difference pixel 2Pconfigured in the above-described manner, it is not required to form alight shielding film on an upper surface of the photoelectric convertingfilm 52 for each color, so that it is possible to realize the phasedifference pixel while avoiding an increase in the number of steps forforming the light shielding film. Also, it is not required to separatethe photoelectric converting film 52 between the pixels, so that it ispossible to inhibit dark current generated when the photoelectricconverting film 52 is separated between the pixels.

Therefore, it is possible to form a more preferable phase differencepixel 2P for detecting a focal point by using the photoelectricconverting film 52 formed on an outer side of the semiconductorsubstrate 12.

Variation of Third Embodiment

Although a layout is such that a normal pixel 2X is arranged adjacent toa phase difference pixel 2P_(A) or 2P_(B) in a vertical direction and ina horizontal direction in an example illustrated in FIG. 8, the layoutmay also be such that the phase difference pixels 2P_(A) and 2P_(B) arearranged adjacent to each other in the vertical direction or in thehorizontal direction as illustrated in FIG. 12.

Also, although it is described that an element separating electrode 81is extended on the assumption that the element separating electrode 81is formed into a lattice shape on a pixel boundary in the verticaldirection and in the horizontal direction in the description above, theelement separating electrode 81 in the lattice shape may be omitted asillustrated in FIG. 13. Also, it is of course possible to configure suchthat the element separating electrode 81 in the lattice shape is omittedfrom the layout illustrated in FIG. 8 and only an element separatingelectrode 83 having an island shape is provided. In this case,predetermined fixed potential is applied only to the element separatingelectrode 83 having the island shape. Furthermore, a shape may be suchthat not an entire element separating electrode 81 in the lattice shapeis omitted but only a part of the element separating electrode 81 in thelattice shape is omitted to form a H shape, for example.

Meanwhile, difference between the element separating electrode 83 in theisland shape illustrated in FIG. 13 and a lower electrode 53 c in anisland shape of a dummy pixel 2D_(AB) of the second embodimentillustrated in FIG. 6 is that the former is connected to metal wiring 82which supplies predetermined fixed potential and the latter is connectedto a FD unit 49 which accumulates a charge. The element separatingelectrode 83 in the island shape illustrated in FIG. 13 may also have anisolated pattern without being connected to the metal wiring 82 formedbelow the same. Alternatively, it is also possible to configure suchthat the element separating electrode 83 in the island shape in FIG. 13is not connected to the metal wiring 82 formed below the same butconnected to the FD unit 49 to accumulate the charge to discharge.

<5. Fourth Embodiment of Pixel>

<Cross-Sectional Configuration of Pixel>

Next, a fourth embodiment is described.

In the above-described first to third embodiments, each pixel 2 receiveslight of all wavelengths of red (R), green (G), and blue (B) by aphotoelectric converting unit 61 and photodiodes PD1 and PD2; however,fourth to sixth embodiments to be described hereinafter are different inthat each pixel 2 receives only light of any of the wavelengths of red(R), green (G), and blue (B).

FIG. 14 being a cross-sectional configuration diagram of the pixel 2 ofthe fourth embodiment illustrates a cross-sectional configuration of aportion corresponding to line Y1-Y1′ in FIG. 3 in which one normal pixel2X and a pair of a phase difference pixel 2P_(A) and a dummy pixel2D_(A) are included.

Comparing the cross-sectional configuration of the first embodimentillustrated in FIG. 4 with the cross-sectional configuration of thefourth embodiment in FIG. 14 being the cross-sectional configurationdiagrams taken along line Y1-Y1′ in FIG. 3, in FIG. 14, a photoelectricconverting film 52 which performs photoelectric conversion on greenwavelength light in FIG. 4 is replaced with a photoelectric convertingfilm 91 which performs the photoelectric conversion on the light of allthe wavelengths of red (R), green (G), and blue (B). Also, thephotodiode PD1 which receives the blue light and the photodiode PD2which receives the red light are not provided in a semiconductorsubstrate 12.

Furthermore, in FIG. 14, a color filter 92 which transmits the light ofthe wavelength of red (R), green (G), or blue (B) is newly providedbetween a high refractive index layer 56 and an on-chip lens 57.

Therefore, only the light of any of the wavelengths of red (R), green(G), and blue (B) which passes the color filter 92 achieves thephotoelectric converting film 91, so that each pixel 2 receives only thelight of any of the wavelengths of red (R), green (G), and blue (B).

Also, a rear surface irradiation type configuration in which thephotoelectric converting unit 61 and the on-chip lens 57 are formed on arear surface side opposite to a surface side on which a multi-layerwiring layer 44 is formed is adopted in the first embodiment illustratedin FIG. 4. On the other hand, in the fourth embodiment in FIG. 14, asurface irradiation type configuration in which the photoelectricconverting unit 61 and the on-chip lens 57 are formed on the surfaceside of the semiconductor substrate 12, the side on which themulti-layer wiring layer 44 is formed is adopted.

More specifically, the multi-layer wiring layer 44 is formed on thesurface side of the semiconductor substrate 12 and a transparentinsulating film 51, a lower electrode 53 a, the photoelectric convertingfilm 91, an upper electrode 53 b, the high refractive index layer 56 andthe like are formed on an upper surface of the multi-layer wiring layer44.

Since the multi-layer wiring layer 44 is formed on the surface side ofthe semiconductor substrate 12, the FD unit 49 which holds the chargegenerated by a photoelectric converting film 52 is also formed on thesurface side of the semiconductor substrate 12. Therefore, in the fourthembodiment, a conductive plug 46 and an insulating film 47 forextracting the charge generated by the photoelectric converting film 91to the rear surface side of the semiconductor substrate 12 are notprovided.

FIG. 15 is a view illustrating a layout example of the color filters 92illustrated so as to correspond to the planar layout in FIG. 3.

The color filters 92 are arranged in Bayer arrangement, for example, asillustrated in FIG. 15.

Meanwhile, although the phase difference pixel 2P_(A) and a phasedifference pixel 2P_(B) are the pixels which receive a green (Gr, Gb)wavelength, the dummy pixel 2D_(A) is the pixel which receives a red (R)wavelength, and a dummy pixel 2D_(B) is the pixel which receives a blue(B) wavelength in the example in FIG. 15, the wavelengths (colors) ofthe light received by the phase difference pixel 2P and the dummy pixel2D are not limited to this example. However, it is desirable that thewavelength of the light received by the phase difference pixel 2P_(A)and the wavelength of the light received by the phase difference pixel2P_(B) are the same. Also, it is possible to make the phase differencepixels 2P_(A) and 2P_(B) white pixels which receive the light of all thewavelengths by using a material which transmits all the wavelengths inplace of the color filter 92. When the phase difference pixels 2P_(A)and 2P_(B) are made the white pixels, the material used in place of thecolor filter 92 may be the same material as that of the high refractiveindex layer 56 and the on-chip lens 57, for example.

<6. Fifth Embodiment of Pixel>

<Cross-Sectional Configuration of Pixel>

Next, a fifth embodiment is described.

FIG. 16 being a cross-sectional configuration diagram of a pixel 2 ofthe fifth embodiment illustrates a cross-sectional configuration of aportion corresponding to line Y11-Y11′ in FIG. 6 in which phasedifference pixels 2P_(A) and 2P_(B) and a dummy pixel 2D_(AB) interposedtherebetween are included.

In the fifth embodiment, a wavelength of light received by each pixel 2is configured so as to be similar to that of the fourth embodimentdescribed with reference to FIG. 14 and an arrangement configuration oflower electrodes 53 c and 53 d is similar to that of the secondembodiment described with reference to FIG. 7.

That is to say, in FIG. 16, color filters 92 in Bayer arrangement isformed between a high refractive index layer 56 and an on-chip lens 57and a photoelectric converting film 91 which performs photoelectricconversion on light of all the wavelengths of red (R), green (G), andblue (B) is formed between the lower electrode 53 c or 53 d and an upperelectrode 53 b. According to this, a photoelectric converting unit 61 ofeach pixel 2 receives only the light of any of the wavelengths of red(R), green (G), and blue (B).

Also, the phase difference pixels 2P_(A) and 2P_(B) are arranged in alinear manner with the dummy pixel 2D_(AB) interposed therebetween.Then, the lower electrode 53 d of the dummy pixel 2D_(AB) arranged inthe center is extended to regions which are vacant due to downsizing ofthe lower electrodes 53 c of the phase difference pixels 2P_(A) and2P_(B) to be formed.

Also, a pixel structure of the fifth embodiment is a surface irradiationtype structure in which the photoelectric converting unit 61 and theon-chip lens 57 are formed on a surface side of a semiconductorsubstrate 12, the side on which a multi-layer wiring layer 44 is formed.

<7. Sixth Embodiment of Pixel>

<Cross-Sectional Configuration of Pixel>

Next, a sixth embodiment is described.

FIG. 17 being a cross-sectional configuration diagram of a pixel 2 ofthe sixth embodiment illustrates a cross-sectional configuration of aportion corresponding to line Y21-Y21′ in FIG. 8 in which one normalpixel 2X and one phase difference pixel 2P_(A) are included.

In the sixth embodiment, a wavelength of light received by each pixel 2is configured so as to be similar to that of the fourth embodimentdescribed with reference to FIG. 14 and an arrangement configuration ofa lower electrode 53 c and an element separating electrode 81 is similarto that of the third embodiment described with reference to FIG. 10.

That is to say, in FIG. 17, color filters 92 in Bayer arrangement areformed between a high refractive index layer 56 and an on-chip lens 57and a photoelectric converting film 91 which performs photoelectricconversion on light of all the wavelengths of red (R), green (G), andblue (B) is formed between a lower electrode 53 a or 53 c and an upperelectrode 53 b. According to this, a photoelectric converting unit 61 ofeach pixel 2 receives only the light of any of the wavelengths of red(R), green (G), and blue (B).

Also, the element separating electrode 81 is formed between the phasedifference pixel 2P_(A) and the normal pixel 2X, and the elementseparating electrode 81 is formed in a region which is vacant due todownsizing of the lower electrode 53 c of the phase difference pixel2P_(A) so as to be extended from a pixel boundary line as illustrated inFIG. 17.

Although not illustrated, in a portion in which the normal pixels 2X ofthe sixth embodiment are adjacent to each other, as in FIG. 9, theelement separating electrode 81 is formed in a position on the pixelboundary. Also, in a portion in which a phase difference pixel 2P_(B)and the normal pixel 2X are adjacent to each other, as in FIG. 11, theelement separating electrode 81 is formed in a region which is vacantdue to the downsizing of the lower electrode 53 c of the phasedifference pixel 2P_(B) so as to be extended from the pixel boundaryline.

Also, a pixel structure of the sixth embodiment is a surface irradiationtype structure in which the photoelectric converting unit 61 and theon-chip lens 57 are formed on a surface side of a semiconductorsubstrate 12, the side on which a multi-layer wiring layer 44 is formed.

In the above-described fourth to sixth embodiments also, positions inwhich the lower electrodes 53 c are formed in the phase differencepixels 2P_(A) and 2P_(B) are symmetrical with each other. Displacementin image occurs between pixel signals from the phase difference pixels2P_(A) and 2P_(B) because the lower electrodes 53 c are formed indifferent positions. It is possible to realize automatic focusing bycalculating a defocusing amount by calculating a phase displacementamount from the displacement in image to adjust (move) an imaging lens.

It is not required to form a light shielding film on an upper surface ofthe photoelectric converting film 91 also in the fourth to sixthembodiments, so that it is possible to realize the phase differencepixel while avoiding an increase in the number of steps. Also, it is notrequired to separate the photoelectric converting film 91 between thepixels, so that it is possible to inhibit dark current generated whenthe photoelectric converting film 91 is separated between the pixels.

Therefore, it is possible to form a more preferable phase differencepixel 2P for detecting a focal point by using the photoelectricconverting film 91 formed on an outer side of the semiconductorsubstrate 12 also in the fourth to sixth embodiments.

Meanwhile, although the structure illustrated as the fourth to sixthembodiments is the surface irradiation type pixel structure, this mayalso be a rear surface irradiation type pixel structure as that of thefirst to third embodiments.

It is possible to change the phase difference pixels 2P_(A) and 2P_(B)to white pixels also in the fifth and sixth embodiments.

Also, a lower electrode 53 d of a dummy pixel 2D of the first to thirdembodiments and the element separating electrode 81 of the fourth tosixth embodiments are the electrodes extending at least to the boundaryof the pixel.

<8. Manufacturing Method of First Embodiment>

Next, a method of manufacturing a pixel 2 according to the firstembodiment illustrated in FIG. 4 is described with reference to FIGS.18A to 25B.

Meanwhile, in FIGS. 18A to 25B, a method of manufacturing a power supplyunit to an upper electrode 53 b not illustrated in FIG. 4 is alsoillustrated.

First, as illustrated in FIG. 18A, photodiodes PD1 and PD2, a conductiveplug 46, a FD unit 49, a conductive plug 122 for supplying power to theupper electrode 53 b and the like are formed in a semiconductor region41 of a semiconductor substrate 12. An outer periphery of the conductiveplug 122 is covered with a SiO₂ or SiN insulating film 123.

Also, a plurality of pixel transistors which reads charges accumulatedin the photodiodes PD1 and PD2 and a multi-layer wiring layer 44 formedof a plurality of wiring layers and an interlayer insulating film areformed on a surface side (lower side in the drawing) of thesemiconductor substrate 12.

Then, as illustrated in FIG. 18B, a transparent insulating film 51A isformed to have a predetermined film thickness on an interface on a rearsurface side of the semiconductor substrate 12.

Next, as illustrated in FIG. 18C, only a region connected to theconductive plug 46 out of the transparent insulating film 51A formed onthe interface on the rear surface side of the semiconductor substrate 12is opened by lithography.

Then, as illustrated in FIG. 18D, a metal material 201 such as tungsten(W), aluminum (Al), and copper (Cu) is formed on an entire surface of anupper side of the transparent insulating film 51A including an openeddug portion of the transparent insulating film 51A.

The metal material 201 formed on the entire surface of the transparentinsulating film 51A is patterned with only a desired region left bylithography as illustrated in FIG. 19A, and according to this, aninterpixel light shielding film 55 is formed.

Furthermore, a transparent insulating film 51B is stacked above thetransparent insulating film 51A and the interpixel light shielding film55 as illustrated in FIG. 19B, and thereafter only a region connected tothe conductive plug 46 out of the stacked transparent insulating film51B is opened again by lithography as illustrated in FIG. 19C.

Then, a metal material 202 is formed on an entire surface on an upperside of the transparent insulating film 51B including an opened dugportion of the transparent insulating film 51B as illustrated in FIG.19D, and thereafter, the metal material 202 on a surface layer isremoved by chemical mechanical polishing (CMP), so that metal wiring 54penetrating the transparent insulating films 51A and 51B is formed asillustrated in FIG. 20A.

Then, an indium tin oxide (ITO) film 203, for example, is deposited onthe transparent insulating film 51B as illustrated in FIG. 20B and ispatterned with only a desired region left by lithography, and accordingto this, a lower electrode 53 a of a normal pixel 2X, a lower electrode53 c of a phase difference pixel 2P_(A), and a lower electrode 53 d of adummy pixel 2D_(A) are formed as illustrated in FIG. 20C.

Furthermore, after the transparent insulating film 51C is formed to havea predetermined film thickness on the transparent insulating film 51Bincluding the lower electrodes 53 a, 53 c, and 53 d as illustrated inFIG. 20D, the transparent insulating film 51C is removed by chemicalmechanical polishing (CMP), for example, until this has the same filmthickness as that of the lower electrode 53 a and the like. As a result,as illustrated in FIG. 21A, the transparent insulating film 51 in FIG. 4is completed by the remained transparent insulating film 51C and thetransparent insulating films 51B and 51A below the same.

Subsequently, a photoelectric converting material 204 which performsphotoelectric conversion on green wavelength light is formed on uppersurfaces of the lower electrodes 53 a, 53 c, and 53 d and thetransparent insulating film 51 as illustrated in FIG. 21B, andthereafter, an indium tin oxide (ITO) film 205 is formed thereafter, forexample, as illustrated in FIG. 21C.

Then, a photoelectric converting film 52 and the upper electrode 53 bshared by the normal pixel 2X, the phase difference pixel 2P, and thedummy pixel 2D are completed as illustrated in FIG. 21D by etching withonly a desired region left.

Subsequently, as illustrated in FIG. 22A, a highly refractive material206A of a nitride film and the like serving as a high refractive indexlayer 56 is formed on upper surfaces of the upper electrode 53 b in apixel region and the transparent insulating film 51 on an outerperipheral portion of the pixel array unit 3.

Thereafter, a contact opening 207 is formed in a place serving as acontact portion of the upper electrode 53 b and a contact opening 208 isformed in a place serving as a contact portion with the conductive plug122 as illustrated in FIG. 22B.

Then, a metal material 209 such as tungsten (W) is conformally depositedon an upper surface of the highly refractive material 206A after thecontact openings 207 and 208 are formed as illustrated in FIG. 23A, andthereafter, this is patterned such that only the outer peripheralportion of the pixel array unit 3 is left as illustrated in FIG. 23B,and according to this, connection wiring 124 which connects theconductive plug 122 to the upper electrode 53 b is completed.

Then, as illustrated in FIG. 24A, a highly refractive material 206B ofthe same material as that of the highly refractive material 206A isfurther formed on the highly refractive material 206A and the connectionwiring 124. The stacked highly refractive materials 206A and 206B serveas the high refractive index layer 56.

Next, after a resin material 210 being a material of the on-chip lens 57is further formed on an upper surface of the high refractive index layer56 as illustrated in FIG. 24B, a photo resist 211 is formed into a lensshape as illustrated in FIG. 25A. Then, the on-chip lens 57 is formed onan uppermost portion of each pixel 2 as illustrated in FIG. 25B byetching back on the basis of the lens-shaped photo resist 211.

The pixel 2 of the first embodiment illustrated in FIG. 4 may bemanufactured in the above-described manner. Meanwhile, the photoelectricconverting unit 61 of the pixel 2 may be similarly manufactured also inthe second to sixth embodiments.

<Application Example to Electronic Device>

Application of the technology of the present disclosure is not limitedto that to a solid-state image sensor. That is to say, the technology ofthe present disclosure is applicable to general electronic devices usingthe solid-state image sensor as an image capturing unit (photoelectricconverting unit) such as an imaging device such as a digital stillcamera and a video camera, a portable terminal device having an imagingfunction, and a copying machine using the solid-state image sensor in animage reading unit. The solid-state image sensor may be in a form of asingle chip, or may be in a form of a module having the imaging functionobtained by packaging an imaging unit, a signal processor, or an opticalsystem.

FIG. 26 is a block diagram illustrating a configuration example of theimaging device as the electronic device according to the presentdisclosure.

An imaging device 300 in FIG. 26 is provided with an optical unit 301formed of a lens group and the like, a solid-state image sensor (imagingdevice) 302 to which a configuration of the solid-state image sensor 1in FIG. 1 is adopted, and a digital signal processor (DSP) circuit 303which is a camera signal processing circuit. The imaging device 300 isalso provided with a frame memory 304, a display unit 305, a recordingunit 306, an operation unit 307, and a power supply unit 308. The DSPcircuit 303, the frame memory 304, the display unit 305, the recordingunit 306, the operation unit 307, and the power supply unit 308 areconnected to one another through a bus line 309.

The optical unit 301 captures incident light (image light) from anobject and forms an image on an imaging surface of the solid-state imagesensor 302. The solid-state image sensor 302 converts an amount of theincident light the image of which is formed on the imaging surface bythe optical unit 301 to an electric signal in pixel unit and outputs thesame as a pixel signal. The solid-state image sensor 1 in FIG. 1, thatis to say, the solid-state image sensor which includes a pixel structureof the above-described normal pixel 2X, phase difference pixel 2P andthe like may be used as the solid-state image sensor 302.

The display unit 305 formed of a panel display device such as a liquidcrystal panel and an organic electro luminescence (EL) panel, forexample, displays a moving image or a still image imaged by thesolid-state image sensor 302. The recording unit 306 records the movingimage or the still image imaged by the solid-state image sensor 302 in arecording medium such as a hard disk and a semiconductor memory.

The operation unit 307 issues an operation command regarding variousfunctions of the imaging device 300 under operation by a user. The powersupply unit 308 appropriately supplies various power sources serving asoperation power sources of the DSP circuit 303, the frame memory 304,the display unit 305, the recording unit 306, and the operation unit 307to supply targets.

As described above, it is possible to realize the phase difference pixelwhile avoiding an increase in the number of steps by adopting thesolid-state image sensor 1 including the pixel 2 according to theabove-described embodiments as the solid-state image sensor 302.Therefore, it is possible to improve a quality of the imaged image alsoin the imaging device 300 such as the video camera, the digital stillcamera, and further a camera module for a mobile device such as acellular phone.

The embodiment of the present disclosure is not limited to theabove-described embodiments and may be variously changed withoutdeparting from the gist of the present disclosure.

In the above-described first to third embodiments, the longitudinaldirection spectral solid-state image sensor including one photoelectricconverting layer (photoelectric converting film 52) above asemiconductor substrate 12 and including two inorganic photoelectricconverting layers (photodiodes PD1 and PD2) in the semiconductorsubstrate 12 is described.

However, the technology of the present disclosure is similarlyapplicable to the longitudinal direction spectral solid-state imagesensor including two photoelectric converting layers above thesemiconductor substrate 12 and including one inorganic photoelectricconverting layer in the semiconductor substrate 12.

Also, although it is described that the organic photoelectric convertingmaterial is used as the photoelectric converting film 52 of thephotoelectric converting unit 61 formed above the semiconductorsubstrate 12 in the above-described embodiments, it is also possible toadopt an inorganic photoelectric converting material. The inorganicphotoelectric converting material includes crystalline silicon,amorphous silicon, and a compound semiconductor such as a Cu—In—Ga—Secompound (CIGS), a Cu—In—Se compound (CIS), a chalcopyrite structuresemiconductor, and GaAs, for example.

Although the planar size of the lower electrode 53 c of the phasedifference pixel 2P is half the size of the lower electrode 53 a of thenormal pixel 2X in the above-described embodiments, there is nolimitation. It is sufficient that the sensitivities of the photoelectricconverting units 61 of the phase difference pixels 2P are asymmetricalwith respect to the light incident angle and the photoelectricconversion regions of the phase difference pixels 2P_(A) and 2P_(B) aresymmetrical to each other.

Furthermore, although the upper electrode 53 b forming the photoelectricconverting unit 61 is formed on the entire surface so as to be shared byall the pixels and the lower electrode 53 a is formed for each pixel inthe above-described embodiments, it is also possible to form the upperelectrode 53 b for each pixel and form the lower electrode 53 a on theentire surface so as to be shared by all the pixels. It is also possibleto form both the lower electrode 53 a and the upper electrode 53 b foreach pixel.

Although the solid-state image sensor in which the first conductivitytype is the P-type and the second conductivity type is the N-type, andan electron is used as a signal charge is described in theabove-described example, the present disclosure is also applicable tothe solid-state image sensor in which a positive hole is used as thesignal charge. That is, the first conductivity type may be the N-type,the second conductivity type may be the P-type, and the conductivitytypes of the above-described respective semiconductor regions may bereversed.

Also, the technology of the present disclosure is applicable not only tothe solid-state image sensor which senses incident light amountdistribution of visible light and images as an image but also to thegeneral solid-state image sensor (physical amount distribution sensingdevice) such as the solid-state image sensor which images incidentamount distribution of infrared rays, X-rays, or particles as an image,or a fingerprint detecting sensor which senses distribution of otherphysical amounts such as a pressure and capacitance and images as animage in a broad sense.

The embodiment of the present disclosure is not limited to theabove-described embodiments and may be variously changed withoutdeparting from the gist of the present disclosure.

For example, it is possible to adopt a combination of all or some of aplurality of embodiments described above.

Meanwhile, the effects described in this specification are illustrativeonly and are not limited;

the effects other than those described in this specification may also beincluded.

Meanwhile, the present disclosure may also have the followingconfiguration.

(1)

A solid-state image sensor including:

a first pixel including a photoelectric converting unit formed of aphotoelectric converting film and first and second electrodes whichinterpose the photoelectric converting film from above and below inwhich at least one of the first and second electrodes is a separatedelectrode separated for each pixel; and

a second pixel including the photoelectric converting unit in which theseparated electrode is formed to have a planar size smaller than theplanar size of the separated electrode of the first pixel and a thirdelectrode extending at least to a boundary of the pixel is formed in aregion which is vacant due to a smaller planar size.

(2)

The solid-state image sensor according to (1) described above, wherein

the third electrode is connected to a charge holding unit which holds acharge generated by the photoelectric converting unit.

(3)

The solid-state image sensor according to (1) or (2) described above,wherein

the third electrode is the separated electrode of an adjacent pixel.

(4)

The solid-state image sensor according to (1) or (2) described above,wherein

the third electrode lies across three pixels including the second pixeland an adjacent pixel.

(5)

The solid-state image sensor according to (1) described above, wherein

the third electrode is connected to wiring which supplies fixedpotential.

(6)

The solid-state image sensor according to (1) or (5) described above,wherein

the third electrode is an element separating electrode formed betweenseparated electrodes of adjacent pixels.

(7)

The solid-state image sensor according to (1) described above, wherein

the third electrode is an isolated pattern which is not connected towiring.

(8)

The solid-state image sensor according to any one of (1) to (7)described above, wherein

the second pixel is a phase difference pixel which generates a signalfor detecting a focal point.

(9)

The solid-state image sensor according to any one of (1) to (8)described above, wherein

the photoelectric converting film is a film which performs photoelectricconversion on light of a wavelength of a predetermined color.

(10)

The solid-state image sensor according to (9) described above, wherein

the photoelectric converting film is a film which performs thephotoelectric conversion on green wavelength light.

(11)

The solid-state image sensor according to any one of (1) to (10)described above, wherein

the second pixel is further provided with an inorganic photoelectricconverting unit in a semiconductor substrate, and

the inorganic photoelectric converting unit performs the photoelectricconversion on light of a wavelength which is not subjected to thephotoelectric conversion by the photoelectric converting unit.

(12)

The solid-state image sensor according to any one of (1) to (7)described above, wherein

the photoelectric converting film is a film capable of performingphotoelectric conversion on light of wavelengths of red, green, andblue.

(13)

The solid-state image sensor according to (12) described above, wherein

a red, green, or blue color filter is arranged above the photoelectricconverting film, and

the photoelectric converting film performs the photoelectric conversionon light which passes through the color filter.

(14)

A method of manufacturing a solid-state image sensor including:

forming a first pixel including a photoelectric converting unit formedof a photoelectric converting film and first and second electrodes whichinterpose the photoelectric converting film from above and below inwhich at least one of the first and second electrodes is a separatedelectrode separated for each pixel, and

a second pixel including the photoelectric converting unit in which theseparated electrode is formed to have a planar size smaller than theplanar size of the separated electrode of the first pixel and a thirdelectrode extending at least to a boundary of the pixel is formed in aregion which is vacant due to a smaller planar size.

(15)

An electronic device including:

a solid-state image sensor including:

a first pixel including a photoelectric converting unit formed of aphotoelectric converting film and first and second electrodes whichinterpose the photoelectric converting film from above and below inwhich at least one of the first and second electrodes is a separatedelectrode separated for each pixel; and

a second pixel including the photoelectric converting unit in which theseparated electrode is formed to have a planar size smaller than theplanar size of the separated electrode of the first pixel and a thirdelectrode extending at least to a boundary of the pixel is formed in aregion which is vacant due to a smaller planar size.

REFERENCE SIGNS LIST

-   1 Solid-state image sensor-   2 Pixel-   2X Normal pixel-   2P Phase difference pixel-   2D Dummy pixel-   3 Pixel array unit-   12 Semiconductor substrate-   PD1, PD2 Photodiode-   41 to 43 Semiconductor region-   49 FD unit-   52 Photoelectric converting film-   53 a Lower electrode-   53 b Upper electrode-   53 c, 53 d Lower electrode-   54 Metal wiring-   56 High refractive index layer-   57 On-chip lens-   61 Photoelectric converting unit-   81 Element separating electrode-   82 Metal wiring-   83 Element separating electrode-   91 Photoelectric converting film-   92 Color filter-   300 Imaging device-   302 Solid-state image sensor

What is claimed is:
 1. A solid-state image sensor comprising: a firstpixel; a second pixel; a third pixel, wherein the first pixel, thesecond pixel, and the third pixel are arranged along a first directionin that order; and a photoelectric converting unit including aphotoelectric converting film that spans the first, second, and thirdpixels, an upper electrode that spans the first, second, and thirdpixels, and a lower electrode comprising a first portion that spans thesecond pixel, a first part of the first pixel, and a first part of thethird pixel.
 2. The solid-state image sensor according to claim 1,wherein the lower electrode comprises a second portion electricallyisolated from the first portion and that spans a second part of thefirst pixel.
 3. The solid-state image sensor according to claim 2,wherein the lower electrode comprises a third portion electricallyisolated from the first portion that spans a second part of the thirdpixel.
 4. The solid-state image sensor according to claim 3, wherein, ina plan view, the first, second, and third portions of the lowerelectrode have at least one line of symmetry.
 5. The solid-state imagesensor according to claim 4, wherein the at least one line of symmetryincludes a line of symmetry along the first direction.
 6. Thesolid-state image sensor according to claim 1, wherein the first pixeland the third pixel are phase difference pixels which generate signalsfor detecting a focal point.
 7. The solid-state image sensor accordingto claim 1, wherein the photoelectric converting film is a film whichperforms photoelectric conversion on light of a wavelength of apredetermined color.
 8. The solid-state image sensor according to claim7, wherein the photoelectric converting film is a film which performsthe photoelectric conversion on green wavelength light.
 9. Thesolid-state image sensor according to claim 1, wherein at least thefirst pixel is further provided with an inorganic photoelectricconverting unit in a semiconductor substrate, and the inorganicphotoelectric converting unit performs photoelectric conversion on lightof a wavelength which is not subjected to the photoelectric conversionby the photoelectric converting unit.
 10. The solid-state image sensoraccording to claim 1, wherein the photoelectric converting film is afilm capable of performing photoelectric conversion on light ofwavelengths of red, green, and blue.
 11. The solid-state image sensoraccording to claim 10, wherein a red, green, or blue color filter isarranged above the photoelectric converting film, and the photoelectricconverting film performs the photoelectric conversion on light whichpasses through the color filter.
 12. An electronic device comprising: asolid-state image sensor including: a first pixel; a second pixel; athird pixel, wherein the first pixel, the second pixel, and the thirdpixel are arranged along a first direction in that order; and aphotoelectric converting unit including a photoelectric converting filmthat spans the first, second, and third pixels, an upper electrode thatspans the first, second, and third pixels, and a lower electrodecomprising a first portion that spans the second pixel, a first part ofthe first pixel, and a first part of the third pixel.
 13. Thesolid-state image sensor according to claim 1, further comprising: afirst lens over the first pixel; and a second lens over the secondpixel, wherein the first portion of the lower electrode overlaps part ofthe first lens and part of the second lens in a plan view.